1. Field of the Invention
The invention relates to an ISDN terminal to communicate in accordance with a procedure of the ISDN.
2. Related Background Art
In the ISDN, terminals of telephones, facsimile apparatuses, and the like can be simultaneously connected to the same bus. Since signals can be transmitted and received between the ISDN and the PSTN, the ISDN terminals and the PSTN terminals can mutually communicate. Among the facsimile apparatuses as ISDN terminals, there is an apparatus having a function to execute the G3 protocol. Such an apparatus can mutually communicate with a G3 facsimile apparatus as a PSTN terminal.
However, when a call is received via the PSTN, the ISDN terminal cannot discriminate whether the call reception is call reception from a telephone or a G3 facsimile apparatus. Therefore, either one of the ISDN telephone connected to the same bus and the ISDN facsimile apparatus having the G3 function which has first responded is connected to the call generation side.
In the case of the call reception from the PSTN G3 facsimile apparatus at that time, so long as the operator has responded by using the ISDN telephone, he can judge that the terminal on the call generation side is a facsimile apparatus. However, the operator cannot perform the facsimile communication.
In the case of the call reception from the PSTN telephone at that time, so long as the ISDN facsimile apparatus having the G3 function has responded earlier than the ISDN telephones, the operator on the call generation side cannot perform speech communication.